Simplify the following expression: $ a = -6 + \dfrac{-7k + 10}{3} $
In order to add expressions, they must have a common denominator. Multiply the first expression by $\dfrac{3}{3}$ $ \dfrac{-6}{1} \times \dfrac{3}{3} = \dfrac{-18}{3} $ Therefore $ a = \dfrac{-18}{3} + \dfrac{-7k + 10}{3} $ Now the expressions have the same denominator we can simply add the numerators: $a = \dfrac{-18 - 7k + 10}{3} $ $a = \dfrac{-7k - 8}{3}$